^ 



^ 



\ 



CONTENTS. 



Letter of submittal 4 

Introduction 5 

Classification of tanning materials 5 

Tannins from woods 6 

Quebracho 7 

Tannin value of quebracho 9 

Utilization of quebracho for tanning 10 

Manufacture of quebracho extract 11 

Process of extraction 12 

Export of Argentine quebracho 13 

Imports of quebracho into the United States 14 

Other Argentine woods similar to quebacho ■ 15 

Tannins from barks 16 

Mangrove bark 16 

Minor barks 19 

Barks of Paraguay 19 

Barks of Argentina 23 

Barks of Brazil 24 

Barks of Chile 24 

Barks of Peru 24 

Barks of Venezuela 24 

Barks of Mexico and Central America 25 

Barks of general occurrence 25 

Barks of the West Indian Islands 25 

Tannins from leaves 25 

Tannins from roots, bulbs, and excrescences 27 

Tannins from fruits and seeds 28 

Divi-divi 28 

Algarobilla 29 

Minor fruits and seeds 31 

Summary 32 

3 



LETTER OF SUBMITTAL. 



\\3> 



Department of Commerce, 
Bureau of Foreign and Domestic Commerce, 

Washington, February 27, 1918. 
Sir: Submitted herewith is a monograph on tanning materials in 
Latin America, prepared by Dr. Thomas H. Norton while he was a 
commercial agent of this bureau. The paper was submitted to the 
Second Pan American Scientific Congress, and was published in 
Volume VIII of the proceedings of the congress. As the edition of 
the proceedings is limited and its distribution confined mainly to 
libraries and Government offices, it has been deemed advisable to 
issue the paper in separate form, to make it more readily available 
to tanners and others interested in the leather industry. 

The monograph presents a comprehensive survey of the tannin- 
bearing plants and trees in South and Central America and Mexico, 
and reveals the resources of these countries, thus far only slightly 
exploited, for meeting the increasing demands for tanning mate- 
rials. Statistics of the Argentine quebracho industry have been 
brought down to the latest possible date. 

Respectfully, B. S. Cutler, 

Chief of Bureau. 
To Hon. William C. Redfield, 

Secretary of Commerce. 
4 



TANNING MATERIALS OF LATIN AMERICA. 



INTRODUCTION. 

Throughout the more densely populated regions of the earth the 
available supply of vegetable material for use in tanning is steadily 
diminishing. 

The importance of a more perfect and exact knowledge of the 
varied substances which contain tannin is now generally recognized. 

In not a few tropical and subtropical lands a more or less complete 
"census" of the trees and shrubs belonging to this category is now 
being taken. 

Few parts of our globe possess such a variety of tannin-bearing 
plants and trees as those included under the designation "Latin 
America." 

It is the purpose of this study to enumerate and describe as com- 
pletely as possible the known occurrence of such sources of tannin 
in the countries in question and to show the extent to which they are 
already utilized or are easily susceptible of exploitation. 

It is highly probable that in many cases the real economic value 
of these American tannin yielders has not been fully appreciated. I 
was led to this conclusion by the appearance during 1913 in a promi- 
nent organ of the leather industry of the following list : 

Geographical Distribution of the Important Tannin Plants. 



India 68 

Europe 40 

Australia 22 

Canada and the United States 16 

Africa 9 

Central America 7 

China 3 

Japan 3 



Chile 3 

Brazil 3 

Argentina 3 

New Zealand : 3 

Peru 2 

Guiana 2 

Asia 2 

Mexico 1 



It will be noticed at once from the above list with what painstak- 
ing care the sources of tannin in the British Colonial Empire have 
been studied. 

CLASSIFICATION OF TANNING MATERIALS. 

Tanning materials, in the broadest meaning of the term, include 
all substances capable of changing the skins of animals into leather. 
By this change the skin ceases to be liable to decay under ordinary 
conditions, becomes more or less soft and pliable, and is, as a rule, 
impermeable to water. 

5 



6 TANNING MATERIALS OF LATIN AMERICA. 

The materials used to accomplish these chemical and physical 
alterations in the nature of hides and skins, are found in all three 
kingdoms of nature. They are likewise found among the products 
of chemical industry. 

The mineral kingdom, for example, furnishes salt and alum, used 
for producing tawed or white leather. 

In many countries animal fats, and notably in the Americas the 
brains of deers, have been employed to make chamois or wash leather. 

Among chemical products such inorganic compounds as the salts 
of copper, iron, cerium, titanium, and notably of chromium, and 
organic aldehydes, especially formaldehyde, have all been used for 
tanning. 

The most important tanning materials are those derived from the 
vegetable kingdom. They include a great variety of woods, barks, 
ieaves, fruits, etc., containing in varying amounts the so-called tan- 
nins or tannic acids. These latter differ widely in chemical consti- 
tution and properties. They all possess in common the power of 
precipitating gelatin from its solution as an insoluble compound. 
They are also all derivatives of the aromatic series, containing either 
pyrocatechol, C c H 4 (OH) 2 , pyrogallol, C 6 H 3 (OH) 3 , or, somewhat 
rarely, phloroglucinol, the isomeride of the latter. The result of 
their action upon the hides of cattle is the production of the brownish, 
yellowish-brown, or reddish-brown leather of commerce. 

This paper will describe such occurrences of the tannins in the 
flora of Latin America as are actually or potentially of importance 
among the world's sources of tanning materials. 

It is manifestly impossible to include in any such list all tannin- 
yielding plants. A tabulation of that character would embrace a 
large part of the vegetable kingdom as represented in the indigenous 
growths of Latin America. 

For the sake of convenience these substances may be classified 
under the following heads : Woods, barks, leaves, excrescences, roots 
and bulbs, fruits and seeds. 

TANNINS FROM WOODS. 

The number of woods yielding tannin in sufficient abundance to 
warrant an industrial exploitation is exceedingly limited throughout 
the world. The woods of the oak and the chestnut form almost the 
only examples in the Northern Hemisphere. 

The past few decades have witnessed the rapid extension of the 
use in tanning of the quebracho wood of Argentina. It may now bo 
regarded as the most important tannin asset of the world. Its 
dominating position is revealed in the import statistics of the United 
States. During the fiscal year ending June 30, 1914, the tanning 
materials brought into the United States were valued at $3,864,000. 
Quebracho wood and extract constituted 87 per cent of the total. 
Quebracho, in fact, formed 38 per cent of all the tanning material 
used in the United States. 

It will thus be easily realized that, while the number of plants 
and trees in Latin America yielding notable amounts of tannin is 
limited, one of these plays the leading role in the world's leather 
industry. 



TANNING MATERIALS OF LATIN AMERICA. 7 

QUEBRACHO. 

The name " quebracho " is derived from the Portuguese " quebrar," 
break, and " hacha," ax. Its literal meaning is " ax breaker." For- 
merly the term was applied to every hardwood tree in South America 
that dulled the chopper's tools. It is now used commercially in 
connection with but three trees, the true quebracho, the white que- 
bracho, and the red quebracho. The latter two are of no importance 
as sources of tannin. Much confusion has resulted from the indis- 
criminate use of the name for totally different varieties of wood. 

The true quebracho, Loxojjterygium or Qwbrackia lorenizii 
Griseb., belongs to the family of the Awacarcliacese, or cashew fam- 
ily, and to the genus Quehrachia. 

It is found in Argentina, Bolivia, Brazil, Paraguay, and Uruguay. 
The more specific habitat is a district extending eastward some 500 
miles from the Andes Mountains, and reaching northward from near 
the mouth of the Parana Elver for a distance of about 600 miles. 
The area of this district is, roughly, 300,000 square miles. The terri- 
tory in which the tree is industrially exploited includes the northern 
portion of Argentina and the Province of Chaco in Paraguay. 

At the present rate of consumption, it is estimated that the annual 
cut of quebracho is much less than the sum total of annual growth. 
The total available supply is estimated at 168,000,000 tons. Less than 
1,000,000 tons are cut annually at present. 

The quebracho is never found in pure stands. It is scattered 
through open forests containing, as a rule, a large variety of species. 
It is rare to encounter more than five quebracho trees per acre. 

In consequence of this scattered occurrence, it is necessary to cut 
annually over about 500,000 acres of forest land in order to secure 
the quantity required to meet the demands of the world's markets. 
The value of the quebracho forest land is quite variable. In Argen- 
tina, when near a railroad, it commands $2 or more per acre. In 
Paraguay the average price is $1.50 per acre, although there are cases 
where the rate is as low as 15 to 25 cents per acre. 

The favorable location for the quebracho tree is on slightly ele- 
vated ridges lying between watercourses. A sandy soil, with moder- 
ate atmosphere but abundant soil moisture, seems also conducive to 
growth. 

Where conditions are very favorable, trees are encountered rang- 
ing in height from 50 to 75 feet and varying in diameter from 2 to 
4 feet. Ordinarily the trees are 18 to 36 feet in. height and 18 to 
40 inches in diameter. The best wood is found in the virgin forests 
along the Parana River and the Picole Majo River. 

Thus far, the tree seems to be immune against the attacks of insects. 

When first felled, the sapwood is of a light yellow color. On ex- 
posure to the sun it assumes a light-red tint. The hardwood, when 
freshly cut, is of a dark, cherry-red color. This deepens with age. 

Quebracho wood ranks among the heaviest and hardest woods 
known. It is the most durable wood found in Argentina. Highly 
tempered tools are needed to work it, even when in the green state. 
After complete seasoning it is exceedingly resistant to cutting tools. 
The specific gravity ranges from 1.27 to 1.38. Ordinarily, 1 cubic 
foot weighs 78 pounds. 



TANNING MATERIALS OP LATIN AMERICA. 




Distribution of the quebracho tree (Quebrachia lorcntzii). 



TANNING MATERIALS OF LATIN AMERICA. 9 

As the quebracho wood is fine-grained and takes a beautiful polish, 
it possesses a pronounced commercial value and is employed locally 
for a great variety of uses — for cabinetmaking, house construction, 
etc. It does not appear, however, that for such purposes it ranks 
above other hardwoods occurring in Argentina. 

Apart from its chief use as a source of tannin, it has been in 
abundant demand in Argentina for many years as a satisfactory 
material for railroad ties. Nine such ties weigh 1 ton. These ties 
remain on a roadbed indefinitely in a state of perfect preservation. 
It has been assumed that the large amount of tannin present acts as 
a preservative and causes the durability. Ties now in use for 25 
years are absolutely sound. 

Throughout the region of occurrence, the quebracho ties are gradu- 
ally replacing the iron or steel ties hitherto used in railroad con- 
struction. The standard ties on the Argentina broad-gauge railway 
are 9 feet long, 10 by 13 inches cross section. They cost $2 to $2.50 
each. On account of the hardness of the wood spikes can not be 
driven into it. Holes are therefore bored and bolts are employed 
to fasten the rails. 

The chief drawback to the use of quebracho wood for this purpose 
is the almost total lack of resilience. There is also a marked tend- 
ency to crack when exposed to frost. The necessity of boring holes 
for the bolts used makes an additional expense. 

Experiments have been started in the United States to test the 
desirability of quebracho ties for our railways. The quebracho 
timberland of Argentina yields, on an average, 18 ties per acre. 
American white oak or pine forests yield from 40 to 60 ties per acre. 

TANNIN VALUE OF QUEBEACHO. 

The tannin content of the different parts of the quebracho tree 
varies somewhat with the region where it grows. Numerous analyses 
give, ordinarily, the following results: 

Per cent 
of tannin. 

Heartwood 20-24 

Sapwood 3- 4 

Bark 6- 8 

One analysis from the Gran Chaco district shows an unusually high 
tannin content : 

Per cent. 
Tannin 28. 20 

Foreign substances extracted 1. 70 

Extract ash : . 40 

Water , 11.85 

Insoluble matter 57. 85 

Jean (Bull. Soc. Chem., 1880, 33, 6) found that the tannin of que- 
bracho was distinctly different from that of oak bark or chestnut 
wood. In 1903, Procter (Leather Manufacture, 269) showed that a 
red phlobophane was present in the tannin, and that it contained 
catechol and phloroglucinol nuclei. 

In 1906, Strauss and Geschwender (Zeitschr. f. angew. Chem., 
19, 1121) isolated the pure tannin, free from phlobophanes. It 

48022°— 18 2 



10 TANNING MATERIALS OF LATIN AMERICA. 

formed a light, flaky mass, easily becoming sticky when exposed to 
the air on account of its hygroscopic character. They consider it as 
identical with maletto tannin, found in the bark of various species 
of eucalyptus, notably Eucalyptus occidentalism and with the tannin 
extracted from cinchona bark. It received the formula of C 43 H 50 O 20 . 

Nierenstein (Collegium, 1905, 65, and Ber. d. deut. ch. Gesell., 1907, 
40, 4575) regards the quebracho tannin as consisting of a mixture 
of three distinct tannins. From quebracho phlobophane, on dis- 
tillation with zinc dust, he obtained anthracene. Incidentally, this 
reaction is worthy of more extended study, as offering a source of 
hydrocarbon for use in the manufacture of alizarin. 

It is definitely established that a considerable amount of the tan- 
nin extracted from quebracho is but sparingly soluble in cold water, 
and is partly deposited when hot aqueous solutions are allowed to 
cool. 

There is still much to be done in clearing up the exact chemical 
nature of the tannin content of quebracho, and it is to be hoped that 
.the problem may be solved in a final manner. It is highly probable 
that a more exhaustive study may pave the way for removing the 
difficulties attendant upon the use of quebracho extract alone for 
tanning purposed. 

In this connection, it may be noted that quebracho wood contains 
a fine yellow dye, fisetin, identical with the dyestuff present in young 
fustic. It is present as a glucoside combined with tannic acid. The 
colors obtained from fisetin are, unfortunately, somewhat fugitive to 
light. Mention may also be made of the " quebracho resin," which 
collects as a thickened juice in crevices of the tree. 

UTILIZATION OF QUEBRACHO FOR TANNING. 

It is worthy of note that, as a rule, the sapwood of the quebracho 
tree and its bark are completely neglected as sources of tannin, and 
are allowed to go to waste. When we consider that chestnut wood 
contains but 3 to 6 per cent of tannin, that oak wood contains but 
2 to 3 per cent, that the tannin content of oak bark is often as low 
as 8 per cent, and yet know that- all three are profitably employed 
on a relatively large scale as sources of tanning extracts, it is a mat- 
ter of surprise that these two constituent portions of quebracho logs 
should be entirely neglected, when once in the possession of extract 
factories. 

There would appear, also, to be a distinct field for experimentation 
on the characteristics of the tannins formed in the sapwood and in 
the bark of the quebracho tree. It is not impossible that they may 
be free, to some extent, from certain disadvantages attending the 
use of the tannin obtained from the heartwood. Almost invariably, 
the tannin present in the heartwood is extracted by boiling with 
water, and the concentrated extract is used for tanning purposes. 

The special field of usefulness for quebracho in the production of 
current forms of leather has now been quite clearly defined. 

In regard to color, quebracho alone does not seem to impart any 
distinctive tint. However, when alum and salt are added to the 
bath, finer results are obtained than when gambier is employed. The 
resultant leather is of a handsome, pale, straw-colored grain on the 
exterior surface, while the flesh side remains almost white. 



TANNING MATERIALS OF LATIN AMERICA. 11 

Quebracho adds weight and firmness to the tanned product. It 
yields a light leather well adapted to take on all varieties of dyes, and 
also heavy leathers of excellent quality. 

Its chief advantages lie in its cheapness and in the ability to effect 
rapidly a thorough tanning, very marked in the case of certain forms 
of leather. It is particularly adapted to tan hide promptly and to 
facilitate the absorption of the very strong liquors employed in the 
final stages of tanning. 

On account of the absence from quebracho extract of certain non- 
tanning substances, occurring ordinarily in the extracts of most tan- 
nin-yielding plants and trees, it fails to produce, alone, the highest 
grade of leather. It is therefore ordinarily mixed with other tan- 
ning materials, such as the extract of mangrove, or chestnut or oak 
bark, all of which are rich in nontannins. When combined with oak 
bark especially, the results are most satisfactory, the cost of tan- 
ning is very notably decreased, and the leather obtained is equal, 
in every respect, to that made by the use of pure oak liquor. 

MANUFACTURE OF QUEBRACHO EXTRACT. 

The cost of cutting quebracho logs and conveying them to the 
extraction factories, or to points of shipment by rail or water, is 
usually much greater than the cost of preparing the extract. Ordi- 
narily, after a tree is felled, the logs (16 to 32 feet in length) are 
freed from bark, sapwood, and branches, and hauled by ox team to 
the nearest factory or railway station or landing place on a river. 
This transportation of the logs is especially difficult and expensive 
in Paraguay, where there is no local market for the wood or the 
extract, As a rule, the Paraguay quebracho is largely shipped to 
Buenos Aires. 

The best timber is frequently reserved for building purposes, for 
cabinetmaking, etc. The culls, or second-quality wood, are employed 
for extractive purposes. 

The extraction industry is very effectively organized in Argentina, 
some of the companies being quite well financed. The recent consoli- 
dation of the Forestal Co. and the Santa Fe Land Co. has placed in 
the control of a single corporation a capital of $10,000,000 and an area 
of forest land exceeding 6,000,000 acres. 

One large Argentine plant has a monthly output of 1,000 tons of 
extract; another produces monthly 600 tons. There are quite a num- 
ber with a monthly output of from 200 to 300 tons. All are equipped 
with modern extractive apparatus, chiefly of German construction. 
Some of the companies were engaged, until recently, in supplying 
railroad ties. They have discovered that the same amount of wood, 
which yields ties worth $3.50, supplies extract worth from $10 to $12. 
In the larger factories, the daily consumption of water reaches sev- 
eral thousand cubic meters. Some factories are located in regions 
destitute of pure, fresh water for the purpose of extraction. As a 
result, all water required for such use must be purified by distillation. 

On the upper Paraguay River there are five plants for making 
quebracho extract, and the machinery is nearly all of German origin. 
The capital invested is partly German, partly Argentine. During 
1912, these factories all ceased operations. This action caused a 
financial panic, as the output of the five works brought into the 
country monthly over $100,000 of foreign money. Since the out- 



12 TANNING MATERIALS OF LATIN AMERICA. 

break of the present war, the price of extract has practically quad- 
rupled and three of the factories are again in active operation. 

PROCESS OF EXTRACTION. 

In most of the extractive factories of Argentina and Paraguay, 
the quebracho logs are first reduced to chips and shavings, by ma- 
chines similar to those used for dyewoocls. It is stated that, in some 
cases, the logs are split into boards, and that the spent boards are 
used later for fence posts, beams, paving blocks, railway ties, etc. 
The sole use for spent material in American works is as fuel. 

The most approved device for chipping the quebracho consists of 
revolving cylinders faced with strong knives. As the logs are 
pressed against these cylinders, the wood is sliced transversely to the 
grain, into chips about one-eighth of an inch in length. 

Formerly, extraction took place in open wooden vats, similar to 
those customarily employed for the extraction of sumac. The re- 
sultant liquor, obtained by diffusion, was better colored, as there was 
no decomposition of tannin, in consequence of the use of heat. The 
leaching was, however, very imperfect. Now, closed extractors of 
copper are in general use. Some of these extractors have a capacity 
of 15 cubic meters (530 cubic feet). Steam is admitted directly. 
The operation is rqpid, and very concentrated liquors are obtained 
in place of the dilute solutions secured by diffusion batteries. These 
concentrated liquors show a strength of 20° B. upward. 

As a rule, they are cooled by circulation through a system of pipes, 
and are clarified by being allowed to stand for some time at a tem- 
perature of 15° C. until most of the insoluble sediment has been de- 
posited. During this operation, light and air are excluded in order 
to prevent oxidation and a resultant darkening of the liquor. 

For a'more complete chemical clarification and decolorization, vari- 
ous substances are in current use, such as. animal blood, lead nitrate, 
alum, sulphurous acid, sulphides, and resin soap. The use of a resin 
soap solution, with finely powdered lead sulphate or barium sulphate, 
seems to give fair results. Better results, however, are ordinarily 
obtained by the Tagliani, or alkaline sulphite^ method. Until this 
process was introduced, the use of quebracho extract was frequently 
attended by the formation on hides of a slimy precipitate, which 
very materially delayed the operation of tanning. An adequate 
treatment with sodium sulphite effectually removes the matters 
which give rise to this precipitate. All the above reagents cause the 
liquor to assume a much lighter tint. 

After clarification and decolorization, the quebracho extract is 
evaporated in vacuum pans to a sirupy consistency. These liquid 
extracts contain from 50 to 60 per cent of water and have a density 
of from 20° to 30° B. The Yaryan evaporator is largely used for 
concentration to 20° B. 

Sometimes the evaporation is carried so far that but 20 to 25 per 
cent of water remains. The resultant extract, on cooling, is solid. 

It is to be noted, in connection with the general process of extrac- 
tion, that from 91 to 93 per cent of the tannin present in quebracho 
wood is extracted, and that but a small amount of nontannins enter 
into solution. In the Argentine factories, but little attempt is made to 
carry the extraction beyond the point at which about 3 per cent of 
tannin remains in the spent wood 












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TANKING MATERIALS OF LATIN AMERICA. 



13 



In the commercial extracts and pastes, it is found that there is 
a considerable amount of tannin present which is not soluble in 
strong tanning liquors. This is an exception to the ordinary rule. 
In all other tannin extracts, the entire quantity of tannin present is 
soluble in the strong liquors. 

A typical sample of quebracho extract, on analysis, showed : 

Per cent. 

Tannin, soluble 64. 5 

Tannin, insoluble 8. 

Nontannins 7. 5 

A set of comparative analyses of a liquid extract and of a paste 
gave the following results : 



Constituents. 



Extract. 



Paste. 



Water 

Tannin 

Nontannins 

Ash 

Insoluble 

Carbohydrates 

Parts of carbohydrates present to 100 parts tan n hi 



Per cent. 


Per cent. 


43.6 


18.7 


48.3 


70.4 


3.8 


7.9 


1.6 


1.5 


2.6 


1.6 


1.5 


1.8 


3.1 


2.6 



The growth of the quebracho industry has been relatively rapid. 
The wood was first seen in Europe at the Paris Exposition of 1867. 
By 1871 several firms in Havre and Antwerp were using it regularly. 
In 1876 it was supplied to tanners in Switzerland and Alsace, and 
along the Rhine. At about the same time the use in Argentine tan- 
neries assumed notable proportions. 

The importation of quebracho wood into Europe began on a large 
scale in 1888. Germany became at once the leading consumer, using 
the new material largely in the production of sole leather. It was 
partly due to this factor that German sole leather began at that date 
to supplant the American article. In 1876 the United States exported 
sole leather to Germany to the extent of 6,400,000 pounds. In 1886, 
the export had sunk to 2,000,000 pounds. In 1906 the export was 
205,000 pounds. 

The growth of the Argentine export of quebracho wood and ex- 
tract is shown in the following table : 

Value of Exports of Argentine Quebracho. 
[Values are given in Argentine pesos: 1 peso equals $0,965 U. S. currency.] 



Years. 



1880. 
1881. 
1887. 



1890. 
1891. 
1892. 
1893. 
1894. 
1895. 
1896. 
1897. 
1898. 
1899. 
1900. 
1901. 



Extract . 



$40, 167 
68,419 
120,474 
119, 224 
317, 156 
595, 701 
431,004 



Logs. 



910,121 
11,016 
5,095 

172, 700 

485,357 

826, 508 
1,245,628 

617, 811 
1,265,942 

962, 687 
1,778,814 

832, 718 
1,356,744 
1,882,604 
1,593,761 
2,398,362 
1, 989, 195 



Years. 



1902 
1903 
1904 
1905 
1906 
1907 
1908 
1909 
1910 
1911 
1912 
1913 
1914 
1915 
1916 
1917 



Extract. 



$909, 904 
1,204,049 
2,011,130 
2,427,772 
2,162,949 
1,811,878 
2,994,922 
4,226,333 
4,429,357 
4,980,027 
4, 836, 860 
4, 974, 686 
5,186,946 
15,873,372 
19, 663, 098 
9, 966, 958 



Logs. 



$2,477,233 
2,002,010 
2, 527, 227 
4,275,164 
3,425,101 
3,132.493 
2,962,1S4 
4, 380; 033 
5,604,430 
6,897,435 
3, 568, 557 
4,988,349 
9, 238, 745 
2,684,408 
2,321,747 
1, 582, 554 



14 



TANNING MATERIALS OF LATIN AMERICA. 



In 1908 the total export of quebracho products from Argentina 
was 254,571 metric tons. The chief countries participating were : 

Metric tons. 

United Kingdom 205,065 

United States 11,949 

Germany : 8, 323 

Italy 7, 282 

In 1913 the total export of quebracho logs and extract reached 
463,648 metric tons. The chief countries participating were: 

Metric tons. 

United Kingdom 83, 035 

United States 37, 835 

Italy 30, 144 

Germany 27, 212 

Belgium 8, 695 

Austria-Hungary 43, 519 

France 3, 891 

In 1913 the value of quebracho products shipped from Argentina 
constituted 2 per cent of the total exports, and stood ninth in 
importance in the list of exported articles. The chief Argentina 
shipping port at that time was Colastine, on the Parana River. 

In 1916 the value of the quebracho products shipped from Argen- 
tina constituted 40 per cent of the total exports, and stood third in 
importance in the list of exported products. The chief shipping 
ports for quebracho in 1915 were Barranqueras (on the Parana 
River in the Territory of Chaco) and Buenos Aires. 

The relations of the American market to the Argentine exports are 
shown in the following table : 

Imports of Quebracho Wood and Extract into the United States, 1907 to 1917. 





Quebracho wood. 


Quebracho extract. 


Fiscal year. 


Tons, 
long. 


Value. 


Pounds. 


Value. 


1907 


66, 810 
48, 871 
66, 113 
80,210 
66,617 
68, 174 

102, 766 
73,911 
54,955 

106,864 
73,367 


$840, 779 
612,971 
731, 795 

1.058,647 
984, 841 
982,315 

1,299,995 
899,603 
753,981 

1,598,465 

1, 274, 660 


76,034,000 
79,187,000 

102,005,000 
87,531,000 
85,721,000 
67,281,000 
74,545,000 
88,589,000 

120, 450, 283 
81,501,952 
59, 808, 734 


$2 320 000 


1908 




1909 

1910 


2,741,000 
2,796,000 
2,894,000 
2,223,000 
1,903,000 
2,441,000 
3,676,749 
5,432,468 
5,198,904 


1911 

1912 

1913 

1914 


1915 


1916 


1917 





The imports of South American quebracho wood and extract into 
Germany during the calendar years 1912 and 1913 were as follows: 

1912. 1913. 

Quebracho wood, metric tons 106,451 117,081 

Quebracho extract, metric tons 12, 158 17, 277 

Exports of quebracho from Argentina to Germany in 1914, accord- 
ing to Argentine statistics, were: Wood, 10,875 tons; extract, 4,054 
tons. 

The British imports of quebracho extract from Argentina aver- 
aged annually in value $163,000 during the five years 1909-1913. 



TANNING MATERIALS OF LATIN AMERICA. 15 

In connection with the importation of quebracho into the United 
States, it is to be noted that no duty has ever been imposed upon the 
logs. Prior to October 3, 1913, there was a duty of one-half cent per 
pound on the extract when below 28° B., and three-fourths cent when 
in excess of that degree of concentration. Since the date above men- 
tioned, quebracho extract has entered the United States duty free. 

The price in 1912 of quebracho logs at Montevideo and at Buenos 
Aires, f. o. b., ranged from $14 to $20 per long ton. The extract was 
then quoted at $80 to $85 per long ton. 

In 1914 the logs destined for export to the United States cost on 
an average $12.17 per long ton at the port of shipment. The average 
cost of the extract at the same points was $61.04. 

In the fiscal year ending June 30, 1915, the average price of logs 
was $13.72 per ton, and of extract, $68.50. In September, 1915, the 
average price of the latter had reached $115 per ton, and the price 
of the logs was $14.98. 

OTHER ARGENTINE WOODS SIMILAR TO TRUE QLEBRACHO. 

There are several other varieties of forest trees in Argentina and 
the neighboring territories containing limited amounts of tannins 
which probably would be utilized as sources of tanning material were 
it not for the abundance of the true quebracho, with its exceptionally 
high tannin content. Allusion has already been made to two of 
these, bearing also the popular designation of " quebracho." 

The white quebracho, " quebracho bianco," Aspidosperma que- 
bracho bianco (Schlecht), belongs to the family of the Apocynacese, 
which includes common dogbane, or Indian hemp. It is very common 
wherever the true quebracho occurs. It is found most abundantly in 
the moister regions of northern Argentina. It is an evergreen tree, 
conspicuous for its erect stem and wide-spreading crown. The height 
frequently ranges from 60 to 100 feet, and the diameter ranges from 
1 to 3 feet. It is easily distinguished from the true quebracho, as the 
branches occur nearer the ground, and the foilage is much less com- 
pact. The wood is strong, hard, and very heavy. The specific 
gravity varies from 0.88 to 1.1. It is very close grained. The color 
is yellowish white, with a noticeable pinkish or rosy tint. Although 
not very durable in contact with soil, it is extensively employed for 
a variety of forms of woodwork. The dense, compact structure ren- 
ders it an excellent substitute for boxwood in wood engraving. 
There is a marked tendency to warp and twist, unless care is taken 
in the seasoning. Unlike true quebracho, it is subject to insect attack. 
The wood contains about 3 per cent of a tannin, which is essentially 
the same as that found in the true quebracho. The leaves, on the con- 
trary, possess on an average 27.5 per cent of a tannin, which is almost 
colorless and is insoluble. The bark contains 4 per cent of tannin. It 
is used locally as a febrifuge. 

The red quebracho, " quebracho Colorado," Aspidosperma que- 
bracho Colorado (Schlecht), belongs to the same family as the white 
variety, and occurs in abundance wherever the true quebracho is 
found. The wood, when freshly cut, possesses a bright red color, 
which changes to a dark brown with age. It is used for the same 
purposes as the white variety. Although it is more durable in con- 



16 TANNING MATEBIALS OF LATIN AMEBIC A. 

tact with the soil, its commercial value is less than that of the allied 
variety. Its tannin content is also quite low. 

Other members of the same family share with the above-mentioned 
varieties the property of hardness, and resemble them in appearance. 
They are: Asptdospermum chwneum, with 7 per cent of tannin; 
Aspidosperma peroba, with 5 per cent; and Aspidosperma sessiflora, 
with 4 per cent. The wood of the latter contains a pink coloring 
matter of possible usefulness. It is a tall, stout tree, at present 
neither well known nor much used. It is found chiefly in Paraguay, 
in a few localities, north of latitude 26°. 

Schinopsis halansce (Engl.), of Paraguay, is reported also to have 
a fair amount of tannin, and to be used locally. 

A member of the sandalwood family, lodina rJiombifolia (H. and 
A.), known as "quebracho flojo" or "" sombra de toro," is a hand- 
some evergreen tree, found occasionally in Argentina. Not only the 
wood, but also the bark, contains fair amounts of tannin. 

Machaerium fertile (Tipuana speciosa), known as "tipa," contains 
much the same amount of tannin in both wood and bark. 

The wood of Cedrela tubifiora, and other varieties of Cedrela, oc- 
curring in Paraguay, contains sufficient tannin to render it available 
for tanning purposes. They are members of a comparatively small 
genus in tropical South America, belonging to the bead-tree family 
(Meliacece) . The trees grow to a large size, and the wood resembles 
mahogany in appearance. 

The wood of young fustic, Rhus cotinus (Linn.), which occurs fre- 
quently in the West Indian Islands, contains a considerable amount 
of tannic acid in combination with the glucoside of fisetin, the hand- 
some but somewhat fugitive yellow coloring matter of this tree. No 
attempt commercially seems to have been made to utilize this source. 
It is worthy of note that cases are very frequent where tannins are 
accompanied by yellow coloring matters. Young fustic is cultivated 
to some extent in Italy, where the leaves are encountered in com- 
merce under the designation of Venetian sumac. They are fre- 
quently used for tanning purposes throughout southern Europe. 

The well-known logwood, Hcematowylon campecManum (Linn.), 
occurring in such abundance in Yucatan, Honduras, San Domingo, 
and Jamaica, is a similar example of the combination of a dyestuff 
with tannin. The value of the coloring principle is such that hith- 
erto there has been no attempt made to secure a tannin extract from 
the wood of this tree. 

TANNINS FROM BARKS. 

There is a much larger variety of tanning material available in the 
barks of different trees of Latin America than is the case with the 
woods. The amount of tannin extracted from quebracho wood alone 
is, however, much greater than the total obtained at present from all 
forms of bark, leaves, and roots. Many of these varieties of bark 
have an extensive local use in the different countries, especially in 
regions where the quebracho does not occur. Thus far they have not 
become of marked importance in international trade. 

MANGROVE BARK. 

The only possible exception to the above statement is found in 
the case of mangrove bark. The export of the bark from Venezuela, 



TANNING MATERIALS OF LATIN AMERICA. 17 

and of the extract of the bark from Colombia, have recently become 
a factor of growing interest in connection with the world's supply 
of tanning materials. 

Hitherto the chief sources of mangrove bark have been Portuguese 
East Africa, Madagascar, and the East Indies (Celebes, Borneo, 
etc.). The bark of the mangrove growing naturally in these regions 
is regarded as distinctly richer in tannin than that found in South 
America, the content ranging from 38 to 48 per cent. 

The mangrove bark of South America comes chiefly from Rhizo- 
phora mangle (Linn.). Other varieties of Rhizophora, as well as 
of Ceriops, Avicennia nitida (black mangrove, or "courouda"), 
Avicennia tomentosa (white mangrove), Laguncularia, Conocarpits, 
and Cassipourea, have a certain importance in this connection. 

The mangrove jungles of tropical America fringe the tidal estu- 
aries, overrun soft marshes, and line low, muddy coasts. The trunks 
and branches emit in abundance adventitious roots which, descending 
in curves, reach the soil at some distance from the parent stem and 
give rise to new trunks. The method of expansion closely resembles 
that of a banyan grove. Another remarkable arrangement of nature 
for the propagation of the tree is connected with the germination 
of the seeds. While the fruit is still hanging to the boughs, long 
radicles emerge from the seeds and descend rapidly to the mud 
beneath. Here, the plumule soon makes its appearance and a new 
growth is established. Some of the fruits and seeds of mangrove 
trees are provided with special devices, which enable them to float 
easily, and to be transported to quite a distance. A novel character- 
istic is found in the " pneumatophores," or air roots. These are 
branches of the root proper which project from the mud. They are 
provided with minute openings, so-called stomata or lenticels, through 
which air enters, and penetrates, by means of passages in the soft 
spongy tissue, to the roots spread beneath the surface of the mud. 

The wood of some species is hard and durable. The fruit of the 
Rhizophora is sweet and wholesome, and serves to produce a light 
wine. It has a ruddy brown shell and a delicate white pulp. 

The percentage of tannin in the bark of mangrove trees is quite 
variable, ranging from 5 to 45 per cent. The proportion increases 
with the age of the tree. The bark encountered in commerce, or used 
for extraction in the country of origin, contains usually from 22 to 
33 per cent. 

The tannin present can be isolated in the form of an amorphous, 
dark-red powder, which so closely resembles in its properties catechu- 
tannic acid that a possible identity is suspected. In practice, man- 
grove extract can be substituted with ease for catechu. A red- 
dish-brown coloring matter accompanies this tannin, and im- 
parts to leather a color quite similar to that resulting from the use 
of hemlock bark. 

It is worthy of note that the leaves of mangrove trees are also 
fairly rich in tannin. They are largely used in the tanneries of 
southern Brazil. On account of the rapid deterioration in properties 
during transportation, they are rarely exported. In the tanneries 
of Santa Catharina, mangrove leaves are the sole material used. The 
annual consumption is about 400 metric tons. In the two tanneries 
of Santos there was in 1902 an annual consumption of 1,800 cubic 



18 TANNING MATERIALS OP LATIN AMERICA. 

meters of mangrove bark, and of 1,350 metric tons of the leaves. 
The same year, 1,000 metric tons of bark and 130 tons of the leaves 
were exported from the port of Santos. 

The bark is encountered in commerce in the form of fragments of 
variable size. It is very hard and very heavy. The cortical cellular 
tissue has a pronounced reddish-brown tint. For local purposes, the 
bark or the leaves are used directly by tanneries, and not submitted 
to extraction. There is now a growing export of mangrove bark, 
especially from Venezuela. The extraction of the tannin, for con- 
venience and economy in transportation, has not yet been as thor- 
oughly perfected as in the case of quebracho. There are, however, 
in Colombia, a few well-organized factories for this purpose. One 
factory at Cartagena, and another at Sinu, 80 miles from the coast, 
are each capable, of producing annually 3,000 metric tons of the solid 
extract. 

The process of manufacturing mangrove extract does not differ 
materially from that employed in producing quebracho extract. The 
bark from the younger steins of the tree surrenders its tannin most 
easily. Care must be taken to avoid the presence of salt, apt to be 
found on the bark, and originating in the salty marshes where the 
tree grows. The liquors, before concentration, are frequently de- 
colorized, or submitted to the bisulphite process, for the removal of 
undesirable substances. The solid product obtained by evaporation, 
in the Colombia factories, contains about 48 per cent of tannin. It 
has a vitreous luster and is very brittle. Extracts from mangrove 
bark of African origin contain from 60 to TO per cent of tannin. 

In tanning operations it is found that mangrove bark, or the ex- 
tract, alone gives an objectionable color to leather. They are, there- 
fore, blended ordinarily with other materials, such as myrobalans. 
In France, a favorite mixture is : 

Per cent. 

Mangrove bark 30 

Hemlock bark 40 

Oak bark 20 

Mimosa bark 10 

This yields an excellent grade of leather, with a fine color. 

On account of the limited amount of soluble nontannins in man- 
grove bark, the baths need to be but very slightly acidulated. The 
value of mangrove bark as a tanning agent for leather, and also as 
possessed of tinctorial properties, appears to have been recognized 
centuries ago in both hemispheres. Its use for coloring basket work 
was established far in the past. The first documentary evidence as to 
the employment of mangrove bark for the above purposes dates back 
to the early part of the sixteenth century, in San Domingo. 

The use of the bark in Europe began in 1804, when British tanners 
included it among their recognized sources of tannin. 

To-day it is regarded as one of the very cheapest forms of tannin 
now available, and its use is widespread. There seems to be every 
reason to expect that in the early future the enormous jungles of 
mangrove in Brazil, Venezuela, and Colombia will become most 
valuable assets. 

The importation into the United States of tanning extracts from 
Colombia, during the fiscal year ending June 30, 1914, amounted to 



TANNING MATERIALS OF LATIN AMERICA. 19 

931,567 pounds, valued at $25,494, or 2.73 cents per pound. Pre- 
sumably these figures applied exclusively to the extract of mangrove 
bark. 

There has been a small import into the United States of mangrove 
bark from both Colombia and Venezuela. In the fiscal year 1914 
Colombia furnished 8 long tons, valued at $80, or $10 per ton ; Vene- 
zuela supplied 87 tons, valued at $1,184, or $13.61 per ton. The im- 
port from Colombia reached 74 tons in 1912; and from Venezuela, 
818 tons in 1910. The total import of mangrove bark into the United 
States, in 1914, was 7,689 long tons. In the fiscal year ending June 
30, 1915, it was 13,040 tons. It attained 21,779 tons in 1912. Nearly 
all comes from the regions bordering the Indian Ocean. 

MINOR BARKS. 

There are a large number of other barks occurring in Latin 
America containing varying quantities of tannin, enough to render 
them at least of local value for the purpose of manufacturing 
leather. They may most conveniently be treated by grouping them 
under the countries where each one occurs most abundantly. 

BARKS OF PARAGUAY. 

A very complete exhibit of the barks occurring in Paraguay 
available for the tanner's use was made at the International Agri- 
cultural Exposition, held in 1910 at Buenos Aires. The catalogue 
of this special exhibit was very full and furnished data of value 
on each variety exhibited. A well-classified study of this exhibit 
was published by Dr. W. W. Stockberger in the Journal of the 
American Leather Chemists' Association, 1912, Volume VII, page 
185. 

The following is a resume of the details given in the above 
sources, adopting Dr. Stockberger's systematic classification. The 
native names follow the botanical designation, in parentheses: 

FAMILY ANONACE^E. 

Rollinia sp. (aratikii gwazii). Tannin content, 4.2 per cent. The 
tree, well known for its fruit, is very common in the forests, and fre- 
quently grows quite tall. The thin bark, abounding in bast fibers, 
is easily removed. 

FAMILY APOCYNACEiE. 

Aspidosperma poly neuron Muell. (palo rosa). Tannin content, 
2.6 per cent. A tall, stout tree yielding excellent timber. It is 
neither well known nor much used. It is of scattered occurrence 
in Parana, north of latitude 26°. A pink coloring matter in the 
wood deserves further investigation. The wood contains also a 
fair amount of tannin, and mention has been made of it in the 
preceding section. 

Aspidosperma quebracho bianco Schlecht (white quebracho). 
Tannin content, 4 per cent. This tree has also been mentioned in 
the preceding section. It is quite abundant in Argentina. The 
leaves contain 27 per cent of tannin and the wood 3 per cent. 



20 TANNING MATERIALS OF LATIN AMERICA. 



FAMILY BIGNONIACEiE. 



Tec.oma ipe araliacea (?) (lapacho). Tannin content, 5 per cent. 
The tree is common and well known and one of those frequently 
used for timber. The bark is easily removed and has a whitish 
fracture. The epidermis and corky portion are cracked or fissured, 
and bast fibers are abundant. 



FAMILY C^ESALPINIACE^E. 



Apuleia praecox Mart, (yhvihra-pere). Tannin content, 10.7 
per cent. The tree is stout, fairly common, and used for lumber. 
The pale yellow bark is smooth and not easily removed. 

Copaifera lansdorfii Desf. (kupaih). Tannin content, 16.6 per 
cent. It is accompanied by a certain amount of resinous matter. 
The tree grows to some size. It is a rare tree except in the forests 
along the course of the river Monda-ih. The bark is thick and of a 
ligneous structure. The fracture is whitish-red, and the corky layer 
readily breaks into small fragments. The fragrant balsam, known 
in commerce as balsam copaiba, was extracted from this tree at an 
early date by the Jesuit missionaries. 



FAMILY EUPHORBIACEJE. 



Alchornea triplinervia Muell. (tapia gwazu-ih). Tannin content, 
11.7 per cent. The tree is abundant and grows to a good size. The 
bark is quite thick and without bast fibers. Its texture is granulose 
and fragile. It is easily removed, and has a reddish fracture. 

Croton succirubrum (?) (sangre de drago). Tannin content, 11.7 
per cent. Resinous matter with a very penetrating odor is present. 
The tree is small. It is rare in the forests of the uplands but abun- 
dant along the rivers. The bark is smooth and easily removed. It 
is thin, quite fibrous, and has a white fracture. 



FAMILY FABACE/E. 



Salbergia sp. (yhsapih-ih). Tannin content, 5.8 per cent. The 
tree is stout and quite abundant. The bark is smooth and readily 
removed. It is slightly ligneous and has a blackish fracture. 



FAMILY GUTTIFERJE. 



Rheedia brasiliensis Planch & Trianan (pakuri). Tannin con- 
tent, 21.6 per cent. A small amount of resinous and coloring mat- 
ters is present. The tree bears fruit, is slender, and attains a height 
of 40 feet and more. The bark is smooth and easily removed. It 
is brittle and has a pale-red fracture. 



FAMILY LAURACEjE. 



Ocotea sp. (yhva-ika). Tannin content, 10.8 per cent. Large 
amounts of a mucilaginous substance are present, The tree is stout, 
tall, of frequent occurrence in the forests and often used for lum- 
ber. The bark contains few fibers and is grayish when freshly 
broken. 



TANNING MATERIALS OF LATIN AMERICA. 21 



FAMILY MELIACE^S. 



Cabralea sp. (cancliarana). Tannin content, 5 per cent (in the 
young bark). The tree attains a good size, is exceedingly abun- 
dant, and is occasionally used for lumber. The mature bark is 
rather thick and somewhat fibrous. It is difficult to remove and 
has a whitish fracture. 

Cedrela tubiflora, (?) (cedro). Tannin content, 12.6 per cent. 
The tree is largely used for lumber and is common throughout Para- 
guay. The bark is quite thick, composed of tenuous and fibrous 
layers superposed. The corky portions are fissured. It is easily re- 
moved and has an irregular, reddish fracture. 

Two other allied species, containing about the same percentage 
of tannin in the bark, are also found in Paraguay. 

Guarea sp. (guare). Tannin content, 10.02 per cent. The tree is 
abundant and of medium size. The bark is easily removed, is lig- 
neous, and has a whitish fracture. 

TricMlia catigua A. Juss. (kaatigua puihta) . Tannin content, 20.5 
per cent. It also contains a large amount of coloring matter. The 
tree is quite common. The smooth bark is easily removed in strips. 
It is readily broken and has a dark-orange fracture. The bark is 
used somewhat for tanning, but gives to the leather an undesirable 
harshness. 

TricMlia Meronymi Griseb. (kaatigua moroti). Tannin content, 23 
per cent. A large amount of a yellow-rose coloring matter is pres- 
ent. The small tree is very common throughout Paraguay. The 
bark is smooth and readily removed in longitudinal strips. It is 
easily broken and has a whitish-red fracture. The bark is frequently 
used locally by tanners and is also employed to dye cotton fabrics. 



FAMILY MIMOSACEuE. 



Enterolobium twiboiiva Mart, (timbo). Tannin content, 22.3 per 
cent. A certain amount of resinous matter is present. The tree at- 
tains a large size, is very common, and is used for lumber. The bark 
is thick and has a corrugated epidermis and woody bast. The frac- 
ture of the young bark is white ; that of the mature bark is reddish. 
It is extensively used by local tanners. 

Inga affinis D. C. (inga gwazu). Tannin content, 25.8 per cent. 
The tree is stout and grows in profusion along the banks of creeks 
and rivers. The bark is smooth, easily removed from the tree, and 
deficient in bast fibers. It is brittle and has a whitish-red fracture. 

Mimosa, sp. (yukeri gwazii). Tannin content, 10.8 per cent. The 
tree possesses spiny branches and is quite abundant in certain locali- 
ties. The bark is thick and its fracture is dark yellow. The epider- 
mis is corrugated and quite ligneous. 

Peltopkorum dubium Taub. (yhvrihra puihta). Tannin content, 
31.2 per cent. A very large amount of coloring matter is present. 
The tree is very common throughout Paraguay and grows at times 
to an unusually large size. The bark is thick and corrugated and 
very ligneous. It is easily detached from the trunk in long strips 
and has a red fracture. 

Piptademia rigicla Benth. (kurupaih-ra puihta). Tannin content, 
28.2 per cent. A moderate amount of coloring matter is present. 



22 TANNING MATERIALS OF LATIN AMERICA. 

The tree attains a great height and resembles the cedar. The bark 
is ligneous, the epidermis checked and corrugated. It is easily de- 
tached from the trunk and has a pale-rose fracture. 

A very similar species of common occurrence known as kurupaih- 
ra moroti, possesses the same tannin content. 

FAMILY MYRTACE.E. 

" Britoa fragrantissima" (?) (yhvaviro). Tannin content, 9.2 
per cent. This small, fruit-bearing tree is found occasionally in 
great abundance. The bark is smooth, thin, and easily removed. 
It is somewhat fibrous and has a whitish fracture. 

Campomanesia guavird (?) (yhvavira). Tannin content, 11.6 per 
cent. The tree is fruit bearing and highly esteemed. It is well 
known and of common occurrence, frequently attaining great size. 
The. bark is thin and fibrous, difficult to remove, and has a whitish- 
yellow fracture. 

Eugenia bra-siUensis,~LsLm. (yhva-poroitih). Tannin content, 43.4 
per cent. The wood contains 11.6 per cent and the leaves 16.6 per 
cent. There is a certain amount of resin and coloring matter present. 
The fruit-bearing tree is well known and very abundant. In certain 
low places it forms dense thickets. It attains a height of 33 feet 
and a diameter of 18 inches. The bark is smooth and closely ad- 
herent to the sapwood, especially when the flow of sap is scanty. 
It is without bast fibers. Externally it is white. The fracture has 
the color of hazel nuts. 

Eugenia michettii Lam. (nanga pirih gwazu). Tannin content, 
28.5 per cent. But little other extractive matter is present. It is 
very abundant in low grounds, on the banks of small streams. It is 
apt to be associated with other species of the same genus, quite simi- 
lar in appearance, and all more or less tanniferous. The bark is thin 
and smooth, somewhat ligneous, with a whitish fracture. 

Eugenia pungens Berg, (yhva viyu). Tannin content, 10.8 per 
cent. This is a fruit-bearing tree, quite as well known and highly 
valued as the yhva-poroitih. It is larger in size, but of less frequent 
occurrence. The bark is thin, smooth, and very difficult to remove 
from the sapwood. The texture is fragile and the fracture has a 
cinnamon color. 

Eugenia sp. (regalito). Tannin content, 15.8 per cent. The tan- 
nin is exceptionally pure. The tree reaches a height of about 23 feet. 
It is less abundant than the allied members of the same genus. The 
bark is smooth, not very thick, and closely adherent to the sapwood. 
It is removable in small pieces. The fracture has the color of 
hazelnuts. 

Eugenia sp. (yhvajhay puihta, gwazii). Tannin content, 28.7 per 
cent. The tree is not abundant. It reaches 20 inches in diameter 
and 40 feet in height. The smooth, thin bark is easily removed. It 
is without bast fibers and has a whitish fracture. 

" Myrtus edulis" (?) (yhva mbopi). Tannin content, 21.8 per 
cent. The thin, smooth bark is somewhat difficult to remove. It has 
a whitish fracture. 

FAMILY PALM^E. 

Cocos romanzofjiana Cham, (pindo). Tannin content, 6.6 per cent. 
This palm tree is abundant in all the forests along the coast. It is 



TANNING MATERIALS OF LATIN AMERICA. 23 

carelessly destroyed in order to obtain the leaves, which constitute an 
excellent forage for draft animals. The bark is often used for tan- 
ning the choicer grades of leather. 

FAMILY SAPINDACEiE. 

AUophyllus edulis Radlk. (kokii). Tannin content, 10 per cent. 
The tree is small and very common. The bark is thin, smooth, and 
difficult to remove. It is without bast fibers and has a yellowish- 
white fracture. 

Cupania uraguensis H. & A. (kambuata). Tannin content, 17.5 
per cent. The tree is of moderate size and is frequently encountered 
in the forests along creeks and rivers. The bark is rather thick and 
closely adherent to the sapwood. It is removable in small pieces by 
hammering. It is ligneous and has a reddish fracture. 

Cupania vemalis Cambess. (yaguarataih). Tannin content, 15 per 
cent. The tree is small and fairly abundant. The bark is smooth, 
somewhat ligneous, and easily removed in large strips. The fracture 
is of a pale-rose color. 

Cupania sp. (ceclrillo). Tannin content, 15.8 per cent. The small 
tree is of scanty development, and is usually found in low places on 
the banks of creeks and rivers. The thin bark is somewhat adherent 
to the sapwood. It is fibrous and has a whitish fracture. The natives 
use it to tan fine skins. 

FAMILY SAPOTACE^E. 

Bumelia obtusifolia R. & S. (pihkasurembiu). Tannin content, 
8.4 per cent. The tree is somewhat abundant and of moderate size. 
The smooth bark is easily removed. It is of a slightly ligneous 
structure. 

It will be noticed from the above that Paraguay is unusually rich 
in varieties of tanniferous barks. A number are of common occur- 
rence and the tannin content is unusually high. In the event, at a 
later date, of any very acute shortage in the world's supply of tan- 
ning materials, the forests of Paraguay alone should be able to con- 
tribute notably toward meeting the demands of international com- 
merce. 

BARKS OF ARGENTINA. 

As already mentioned, the bark of the true quebracho contains 
from 6 to 8 per cent of tannin. That of the white quebracho con- 
tains 4 per cent. About the same quantity is present in the bark of 
the red quebracho. Fair amounts of tannin are also present in the 
barks of other trees, already mentioned in connection with the tan- 
nin content of the heart wood, such as " tipa," " quebracho flojo," and 
varieties of Cedrela, all occurring in Argentina. 

To these may be added the two trees called popularly " cebil." 
They occur abundantly in several provinces of Argentina, notably in 
Salta and Jujuy, remote from quebracho forests, and are extensively 
used by the tanners of such sections. 

Piptademia cebil (Griseb.), red cebil, contains from 15 to 25 per 
cent of tannin in the bark and from 6 to 7 per cent in the leaves. 

Acacia cebil (Griseb.) contains 8 to 12 per cent of tannin in the 
bark and 7 to 8 per cent in the leaves. 

Mimosa farinosa (Griseb.). The bark contains 3.9 per cent of 
tannin. 



24 tanning mateeials op latin America. 

BARKS OF BRAZIL. 

The tree known as Barbatimao (8 'try phnodendron Barb atimdo), 
occurs in abundance in the State of Minas Geraes, in the south of 
Brazil. The bark is stated to contain as much as 60 per cent of 
tannin. The price at present is $30 per metric ton, laid down in 
Sao Paulo or Rio de Janeiro. It makes an excellent leather. 

The angico tree is found also in Minas Geraes. The bark contains 
28 per cent of a very light-colored tannin, highly valued by tanners. 
The price at the seaboard is the same as that of Barbatimao. 

Remoteness from industrial centers, and the high cost of transpor- 
tation have hampered any attempt to exploit these barks on an 
extensive scale. 

Eugenia jembos (Linn.) contains 12.4 per cent of tannin. 

The following is a list of the local names of barks found in Brazil, 
which have a very limited use in tanning: Arica, cannella, garabi, 
genubata, grannaniamba, guabari, hyrsonima, mimusops, monesia, 
pimento, santarita, schinus mollis, trumpet-wood, vanigra. 

BARKS of chile. 

Eucryphia cordifolia Cav. (ulmo). The tree occurs in abundance 
in Chile. The bark is largely used in local tanneries, and the extract 
is exported to some extent. This extract is of a dark-red color, and 
strongly resembles that obtained from mangrove bark. The United 
States purchases annually a small quantity of this extract, valued at 
about $8,000. 

Persea lingue (lingue). Enormous forests of this tree occur in 
southern Chile. The reddish-brown, soft bark contains from 20 to 
24 per cent of a tannin, which is very easily extracted by water. It is 
of extended use locally for the production of the well-kno^n Val- 
divia leather. It has been used to some extent in Great Britain in 
tanning leather to serve for uppers. 

Laurus peumo. The bark of this tree also serves locally for mak- 
ing upper leather. 

BARKS OF PERU. 

The bark of the cascara tree is reported to be in extensive local use 
for tanning purposes. 

The alkaloids present in cinchona bark are largely in combination 
with quinotannic acid. No attempt has been made to utilize this con- 
stituent of Peruvian bark, as far as is known. 

BARKS OF VENEZUELA. 

Teeoma pentaphylla (roble Colorado). The bark of this tree con- 
tains 27 per cent of tannin, which is accompanied by a soluble, 
orange-red coloring matter. 

Teeoma leucoxylon (Mart.). This allied variety occurs chiefly in 
Guiana, where the bark is regularly employed in tanning. 

Weinma.nnia glabra. The bark has a limited use. The wood of the 
tree is highly valued for cabinet work. 

In addition to the above, the barks of the following Venezuelan 
trees are occasionally employed by tanners: Aguacate, botoncillo, 
coco palm, gateodo, simaruba, tamarindo, yagrumo, and urape. 



TANNING MATERIALS OP LATIN AMERICA. 25 

BARKS OF MEXICO AND CENTRAL AMERICA. 

Oak bark is widely used for tanning throughout Mexico. The 
local varieties employed for this purpose are Quercus xalapensis 
(Encinos), Q. castanea, and Q. imbricaria (laurel oak). The last 
mentioned is also found in Guatemala and used there for tanning. 

Mimosa huamuchil. The bark of this variety of mimosa is widely 
used, especially in Oaxaca, for making suede leather. 

Pithelocolobium dulce (huamuchil 6 pinzan). The bark is used 
extensively in Jalisco and Morelos, in tanning saddle and harness 
leather. 

Lysaloma Candida (palo bianco). The bark is frequently used. 

Acacia malacophylla 6 mimosa sp. (timbre 6 timbre). This bark 
is employed largely to tan leather intended for bookbinding and for 
shoemakers. 

Mimosa biuncifera 6 acaci-a, sp. (una de gato) . In Michoacan, this 
is used in tanning black goatskins. 

Calliandra grandiflora (Raicilla). Employed in Morelos for 
making soft leathers. 

Bursera microphylla (Torote) and Entorobium cyclocarpum 
(Huincastle). The bark of both trees are of a very limited use in 
Mexico. The latter occurs also in Central America. The pods, as 
well as the bark, are said to be rich in tannin. 

Malpighia punici folia (nancite or manquitta). The tree is abun- 
dant in Nicaragua and in the West Indies. The bark contains from 20 
to 30 per cent of a very light-colored tannin. 

BARKS OF GENERAL OCCURRENCE. 

Brysonima (Murici). 

Stryphnodendron barbatimum (Mort.) (tuga veca). The bark 
yields the amorphous Barbatimao tannic acid, an amorphous red 
powder. Both of the above are of scattered occurrence. 

BARKS OF THE WEST INDIAN ISLANDS. 

In the West Indian Islands several trees and vines occur, the barks 
of which contain tannin in industrial quantities. They may be 
briefly enumerated in order to complete the geographical survey. 
They are: Carapa guianensis (crab-wood) ; spondias lutea (hay 
plum) ; lecythis ollaria (kararalli) ; mora excelsa (mora) ; coccoloba 
uvifera (seaside grape), source of a Kino; nectandra (sirnahelli) ; 
bloodwood; baromalli or pump wood; cuyama. 

TANNINS FROM LEAVES. 

There are but few representatives in this class. Mention has already 
been made of the tannin present in the leaves of the white quebracho 
of Argentina, and of the extent to which the leaves of mangroves 
are employed in the tanneries of southern Brazil. 

The leaves of yhva-poroitih, Eugenia brasiliensis Lam., so abun- 
dant in Paraguay, contain, when air-dried, 16.6 per cent of tannin. 
They might advantageously be made the object of systematic an- 
nual exploitation, for the purpose of extracting the tanning principle. 

Guaiacum arborewn (molle-guayacan). The leaves are locally 
used for tanning in various tropical regions. The tree is closely 
allied to Guaiacum officinale, the well-known lignum-vita3. 



26 TANNING MATERIALS OF LATIN AMERICA. 

Sumac, obtained in Mexico from the leaves of Rhus aromatica 
(Ait.) and Rhus copallina (Linn.) is the most important member of 
this category. The dry leaves contain about 13 per cent of tannin. 
Mention has already been made of the value of young fustic wood as 
a source of tannin. The leaves of this tree, Rhus cotinus, contain 
17 per cent of tannin. They could also be profitably made the object 
of a systematic harvesting. These leaves bear easily sea transporta- 
tion. The different varieties of Rhus can advantageously be culti- 
vated, as is now the case in Italy. 

The tannin of sumac leaves is very similar to that present m myro- 
balans, but is somewhat paler in color. It is principally used in the 
production of light leathers. Sometimes warm sumac liquor is em- 
ployed to brighten the color of heavy tannages. As a rule, the Amer- 
ican varieties are less adapted for making white leather than the 
Sicilian sumac, on account of the presence of a certain amount of a 
dark coloring matter. It is to be noted that leather made by the 
use of sumac tannin is not very resistant to water. 

Aspidosperma quebracho bianco (Schlecht). This tree, the "white 
quebracho" of Argentina, has already been described as having a cer- 
tain amount of tannin in its wood, viz, 3 per cent. Its bark contains 
also 4 per cent. The leaves are, however, remarkably rich in tannin, 
the average amount present reaching 27 per cent. There is probably 
no other tree occurring abundantly in South America, the leaves of 
which possess as much value from the tanner's standpoint. No at- 
tempt appears to have been made to exploit this source of tannin, 
probably on account of the great abundance of the true quebracho, 
side by side with the white quebracho. 

In connection with the consideration of the bark of the mangrove, 
Rhizophora mangle (L.), attention has already been directed to the 
value of the leaves, as rich in tannin, and to their extensive use in 
the tanneries of southern Brazil. 

One of the most interesting occurrences of tannin in the leaves of 
South American flora is that connected with Paraguay tea, or "yerba 
de mate." The dried leaves and shoots of Ilex paraguensis (A. St. 
Hil.) are now used by over 30,000,000 inhabitants of South America 
to make an infusion which, as a beverage, replaces the tea or coffee 
of other regions. 

The tree is an evergreen, closely related to the holly, and grows 
abundantly in the mountain forests of Argentina, Paraguay, and 
southern Brazil. In height it ranges from 15 to 30 feet. The leaves 
are 4 to 6 inches long, lanceolate, with finely serrated margins. 

Infusion is made as in the case of Chinese tea. The so-called mate 
thus obtained is regarded as having valuable restorative qualities 
when taken after violent or prolonged physical exercise. It also 
possesses mildly aperient and diuretic properties. The caffeine pres- 
ent is not much in excess of 1 per cent, as compared with 3.5 to 4.5 
per cent in teas of oriental origin. The physiological action of the 
tea, therefore, seems to be narcotic rather than stimulative. 

The tannin present in the leaves is also much less than in the case 
of ordinary tea leaves, being on an average about 1.5 per cent. This 
tannin is very peculiar in character, as it does not precipitate po- 
tassio-tartrate of antimony, and is totally without action on hides 



TANNING MATERIALS OF LATIN AMERICA. 27 

and skins. Thus far this tannin remains more of a scientific curiosity 
than an article of commercial interest. 

TANNINS FROM ROOTS, BULBS, AND EXCRESCENCES. 

This category has also but a very few representatives in Latin 
America. There are no tannin-bearing excrescences similar to the 
nutgalls of Syria and China or the knoppern of Austria, and the 
number of roots is quite small. 

Fuchsia macrosieTrvma (churco). The root bark of this Chilean 
plant contains 25 per cent of a bright-red tannin. The bark is thin 
and brittle, and the tannin is easily extracted. It is used locally 
in Chile for making leather. 

Krameria trianria (Ruiz et Pa v.) (rhatany). This plant grows 
in abundance on the slopes of sandy mountains in Peru. The root 
is woody and branched. The cortex is fibrous, of a reddish-brown 
color, and is easily separated from the central, reddish-yellow, woody 
part. It has no smell, but is exceedingly astringent, without being 
bitter. In commerce it is usually found in the form of powder. 

The tannin content ranges from 38.3 to 42.6 per cent. It is much 
more abundant in the cortex than in the core. In a pure form it is 
a light yellow powder, quite soluble in water. The extraction by 
this means is very simple. A certain amount of the concentrated 
extract is exported. This is not used in tanning alone, but gener- 
ally as an addition to other liquors. Euiz, the botanist, was first 
led to investigate the nature of the root, having noted that it was 
used by women for rubbing the teeth and strengthening the gums. 

Rumex hymenosepalus (Torr.) (canaigre). This plant, known as 
the sour dock, or wild rhubarb, grows abundantly in those parts of 
Mexico, seldom visited by rain, where the average temperature is 
below 20° C. The plant grows to a height of about 3 feet. For cen- 
turies the natives of Mexico have used the air-dried, tuberous roots 
as a material for tanning hides. The name of sour cane (call na ger) 
was given the plant by the early missionaries, and this was gradually 
changed into canaigre. 

The roots weigh each from one-half pound up to 2 pounds. They 
live for five years in the soil. In practice they are gathered when 2 
years old. In commerce canaigre is encountered in the form of red- 
dish disks or as a liquid extract. The plant is cultivated to some 
extent. It is, in fact, the only tanniferous plant in Latin America 
which can be profitably made the object of systematic culture. 

Tannin is found in all parts of the plant — stalk, leaves, flowers, 
seeds, and roots — -but chiefly in the last mentioned, which greatly re- 
semble dahlia roots in appearance. The percentage of tannin is 
exceedingly variable, depending upon the conditions of growth. An 
adverse environment favors a high percentage. On the contrary, in 
a rich, well-irrigated soil the percentage is low. During the annual 
period of growth the tannin content increases most rapidly at the 
beginning of summer, when the plant is dying back to the ground. 
At this period the astringent sap of the leaves retreats into the roots, 
thus contributing materially to heighten their percentage of tannin. 
Young roots 3 to 7 inches in length and nearly an inch in thickness 
contain 10 per cent of tannin. In roots that are 2 or 3 years old 
the amount present reaches 28 per cent. Trimble states that the 



28 TANNING MATEEIALS OF LATIN AMERICA. 

pure tannin, which is much like that of mimosa bark, is a yellowish- 
white powder, readily soluble in water. On boiling with 2 per cent 
hydrochloric acid it yields an insoluble, red phlobophane, together 
with some protocatechuic acid. 

The tannin is accompanied by certain red and yellow coloring 
matters, which are extracted at the same time and distinctly affect 
the quality of canaigre-tanned leather. When a fresh root is cut 
the surface blackens on account of the dyestuff present. Canaigre 
root contains also from 5 to 8 per cent of starch, which must be re- 
moved by some suitable process in order to obtain good results. 
Hence, when an extract is prepared the temperature is maintained 
at from 30 to 50° C. 

Typical analyses of air-dried roots give : 

Per cent. 

Water 1 14. 7 

Tannin 27.8-34.9 

Nontannins 9. 4-18. 1 

Ash l : 1.9-2.1 

Insoluble 33.9 

Carbohydrates 6. 8 

To 100 parts of tannin come 23 parts of carbohydrates. 

The dried root and its extract have given very satisfactory results 
in the tanning of nearly every form of leather. The best results, as 
regards weight and firmness, are obtained in the finishing of harness 
leather and in making various light leathers. On account of the 
easy solubility of the tannin the whole operation of changing hides 
into leather proceeds with great rapidity. When used alone canaigre 
imparts to leather a distinctive orange color. 

TANNINS FROM FRUITS AND SEEDS. 

This group is more numerous than the two preceding groups, and 
some of its members are commercially of importance. 

DIVI-DIVI. 

Ccesalpinia coriaria (Willd.) (divi-divi, also libi-libi). The tannin 
is found in the seed pods. The tree grows to a height of 20 to 30 
feet, and is indigenous in the West Indian Islands, Mexico, Ven- 
ezuela, and northern Brazil. Its pods are about 3 inches long and 
three-fourths inch broad. They are very thin and smooth. After 
drying they frequently resemble in shape the letter S. The color is a 
chestnut brown. 

The pods contain from 40 to 45 per cent of a tannin very similar 
to that present in valonia. This tannin is most abundant in the tis- 
sue of the pod, under the epidermis. There is little in the seeds. A 
typical analysis of the pods gives the following results : 

Per cent. 
Water 1 13. 5 

Tannin 41. 5 

Nontannins 18. 

Ash 1. 6 

Insoluble 25. 4 

Carbohydrates 8. 4 

To 100 parts tannin come 20.2 parts carbohydrates. The tannin 
consists of a mixture of ellagitannin and gallotannin. It is accom- 
panied by a considerable amount of oily and mucilaginous matter. 



TANNING MATERIALS OF LATIN AMERICA. 29 

Divi-clivi tannin is easily separated, in the form of a concentrated 
extract. This latter, as well as the ordinary solutions for tanning 
purposes, on account of the presence of the above-mentioned foreign 
matters, are liable to undergo sudden fermentation, especially during 
electrical storms. In the course of fermentation a deep-red coloring- 
matter is developed, which imparts to leather a dark stain. It is a 
problem not yet solved how this fermentation may be effectively 
avoided. The use of ordinary antiseptics has been of some assistance 
as a preventive. 

Divi-divi is an exceedingly cheap source of tannin. Its use is, 
however, not very extended. As a rule, it is mixed with various barks 
or their extracts. Leather made by the use of divi-divi extract alone 
is apt to be firm in dry weather but soft and spongy in damp weather. 
Ordinarily it is used as a substitute for gambier in the dressing of 
leather and in the rapid drum-tanning of light leathers. Sometimes 
its use in connection with leather is simply as a dyestuff. 

Divi-divi was first imported from Caracas, in 1769, by Spaniards. 
By 1848 it had come into widely extended use. The chief ports of 
shipments are Caracas and Maracaibo. 

The name is said to be derived from David Davis, the captain of 
the first ship to bring to Europe a cargo of the pods. 

The present consumption of divi-divi pods in the United States is 
not large. During the fiscal year ended June 30, 1914, 29,000 pounds 
were imported. The price per pound at the ports of shipment was 
1.6 cents. The best known marks are Curacao, Maracaibo, and Monte 
Christo. Shipments are chiefly from Maracaibo, Parahiba, and Santo 
Domingo. 

The consumption of divi-divi in Germany is much more important. 
During 1913 the exportation from Colombia amounted to 951 metric 
tons and from Venezuela to 5,092 tons. The average value per 
metric ton at the ports of shipment was $4.76. 

Ccesalpinia tinctoria (H. B.K.; Berth.) (Bogota divi-divi). Ccesal- 
pinia sigyna (Eottl.) (tari). The pods from these varieties, as well 
as the so-called " false divi-divi," from other members of Cwsalpinia, 
differ but slightly from those of G. coriaria in appearance and tannin 
content, and are occasionally encountered in commerce. 

ALGAROBILLA. 

Ccesalpinia brevifolia (algarobilla; algarobito; algarobo). This 
plant occurs in sandy, dry regions of northern Chile, and also in 
Colombia. The pods, which contain three to six seeds, are cylindri- 
cal in form, sometimes curved, sometimes straight. 

These pods contain from 35 to 53 per cent of tannin, which is very 
readily extracted. This tannin appears to be a mixture of ellagitan- 
nin and gallotannin. It lies in semiresinous particles, adhering 
loosely to the somewhat open framework of the fiber. It is accom- 
panied by notable amounts of a yellow coloring matter. 

A typical analysis is the following: 

Per cent. 

Water *__ 13. 5 

Tannin 43. 

Nontannins 20. 

Ash 1. 6 

Insoluble 21.9 

Carbohydrates 8. 2 



LIBRARY OF CONGRESS 



30 TANNING MATERIALS OF LATIN AMElx^. ° 16 ° 58 693 A 

To 100 parts tannin come 19 parts of carbohydrates. Concen- 
trated extracts of algarobilla tannin are easily prepared. They are, 
however, as in the case of divi-divi extract, although to a less degree, 
somewhat prone to undergo fermentation. 

When used in tanning, algarobilla gives much better weight and 
greater firmness than is the case with divi-divi. It is also less liable 
to cause discoloration of the leather. The best grades yield a light- 
colored liquor, which colors leather but slightly, imparting a light, 
reddish-yellow tint. After the extract has undergone fermentation 
it produces a leather of an exceedingly bright color. Experience has 
shown that it gives inferior results for sole leather, and that in gen- 
eral, when employed alone, the leather produced is apt to mold in 
the sheds. It is, therefore, in almost all cases, blended with other 
tanning materials, its exceptionally high tannin content serving to 
strengthen the weaker liquors. It is usually blended with myro- 
balans, divi-divi, quebracho extract, or hemlock extract. In prac- 
tically all cases it can replace catechu for blending. 

In consequence of its dyestuff content, algarobilla is occasionally 
used simply as a coloring material, especially on leather. 

Algarobilla is one of the very strongest tanning matters known. 
There are, however, some closely allied trees in Chile, which yield 
pods of an even higher tannin content. They are: Balsamocarpum 
brevifolium, 65 per cent of tannin; Prosopis pallida, 60 per cent; 
and Prosopis dulcis, 62 per cent. They are less abundant, but the 
pods are held locally in high esteem. 

Data on the commercial movement of algarobilla are lacking. 

Ccesalpmia cacolaco (cascalote). The tree is very abundant in 
several districts of Mexico, and the pods have formed from time 
immemorial the chief tanning material of the country. Toluca is 
the most important point of distribution of the product. Other cen- 
ters are the towns of Iguala, Morelia, Patzcuaro, Uruapan, and 
Zitacuaro. 

The tannin content is very high. Cascalote has an advantage over 
divi-divi, in containing a much lower percentage of mucilaginous 
substances. It gives good results in the manufacture of sole leather, 
and most other forms of leather, including morocco, glazed kid, box 
calf, enameled colt, pigskins, etc. 

The native method of tanning with the aid of cascalote is exceed- 
ing^ novel. Prepared hides are first placed for two days in a vat 
with a " weak " or " sweet " tan liquor, until the hides have uniformly 
taken the color. They are then removed and sewn up into bags, 
roughly reproducing the original shape of the animal. These are 
filled with a stronger tan liquor and a quantity of ground cascolote. 
The filled hides are then placed in rows on the pavement of the 
tannery court. The liquor slowly oozes out, and flows into a central 
pit, whence it is pumped from time to time to refill the hides. The 
strength of this liquor is retained by new additions of cascalote. The 
operation continues for about 15 days. For a part of the time the 
bags are piled upon each other, to the extent of six or eight tiers. 
The pressure on the lower tiers increases the rate at which the liquor 
oozes through the hides, and produces a remarkably good tannage. 
The liquor is finally withdrawn, the sewing ripped out, and the hides 
are placed in a lay-away vat for a week or longer. They are then 
ready for the finishing processes. 



Conservation Resources 
Lig-Free® Type I 



LIBRARY OF CONGRESS 



016 058 693 P 9 




